Funds are requested for the purchase of a JEOL 1200-EX transmission electron microscope. An estimated 28 hr/wk of electron microscopy is required for 6 existing NIH grants and sufficient time will not be available on existing instruments. At Colorado State University there is one 4-year-old Philips 400T, one 7-year-old Hitachi HU-12A and seven 11- to 18-year-old transmission electron microscopes. By December 1984, no more than 5 to 10 hr/wk will be available on existing instruments capable of providing high-resolution micrographs. The instrument is requested for research in reproductive biology. There are 9 reproductive biologists associated with the Animal Reproduction Laboratory of which 7 use electron microscopy as an integral part of their research. The majority of the major user group has had long-term funding from NIH. The University's commitment to research and training in reproductive biology is exemplified by plans to construct a 22,000 sq. ft. building to consolidate the faculty and students of the Animal Reproduction Laboratory. This facility will be located about 4 miles from existing electron microscopic facilities. The new building includes space for an electron microscope, and appropriate ancillary equipment, and is scheduled for occupancy in December 1984. Award of a Shared Instrumentation Grant will ensure the availability of the necessary electron microscope. Without such funding the acquisition of an electron microscope is unlikely. The instrument will be operated on a user-fee basis designed to cover operational and maintenance costs. The University has made definitive commitments for the establishment and maintenance of a functional electron microscope facility as a part of the Animal Reproduction Laboratory. The principal investigator is experienced in managing a multi-user electron microscope facility. Appropriate technical support staff are available.